Addition of a Water-Soluble Propofol Formulation to Preservation Solution in Experimental Kidney Transplantation

Future Directions in Optimizing Anesthesia to Reduce Perioperative Acute Kidney Injury

BACKGROUND

Perioperative acute kidney injury (AKI) is common in surgical patients and is associated with high morbidity and mortality. There are currently few options for AKI prevention and treatment. Due to its complex pathophysiology, there is no efficient medication therapy to stop the onset of the injury or repair the damage already done. Certain anesthetics, however, have been demonstrated to affect the risk of perioperative AKI in some studies. The impact of anesthetics on renal function is particularly important as it is closely related to the prognosis of patients. Some anesthetics can induce anti-inflammatory, anti-necrotic, and anti-apoptotic effects. Propofol, sevoflurane, and dexmedetomidine are a few examples of anesthetics that have protective association with AKI in the perioperative period.

SUMMARY

In this study, we reviewed the clinical characteristics, risk factors, and pathogenesis of AKI. Subsequently, the protective effects of various anesthetic agents against perioperative AKI and the latest research are introduced.

KEY MESSAGE

This work demonstrates that a thorough understanding of the reciprocal effects of anesthetic drugs and AKI is crucial for safe perioperative care and prognosis of patients. However, more complete mechanisms and pathophysiological processes still need to be further studied.

The Effect of Antioxidant Added to Preservation Solution on the Protection of Kidneys before Transplantation

Ischemia–reperfusion injury is a key clinical problem of transplantology. Current achievements in optimizing organ rinse solutions and storage techniques have significantly influenced the degree of graft damage and its survival after transplantation. In recent years, intensive research has been carried out to maintain the viability of tissues and organs outside the integral environment of the body. Innovative solutions for improving the biochemical functions of the stored organ have been developed. The article discusses directions for modifying preservation solutions with antioxidants. Clinical and experimental studies aimed at optimizing these fluids, as well as perfusion and organ preservation techniques, are presented.

Experimental models of acute kidney injury for translational research

Preclinical models of human disease provide powerful tools for therapeutic discovery but have limitations. This problem is especially apparent in the field of acute kidney injury (AKI), in which clinical trial failures have been attributed to inaccurate modelling performed largely in rodents. Multidisciplinary efforts such as the Kidney Precision Medicine Project are now starting to identify molecular subtypes of human AKI. In addition, over the past decade, there have been developments in human pluripotent stem cell-derived kidney organoids as well as zebrafish, rodent and large animal models of AKI. These organoid and AKI models are being deployed at different stages of preclinical therapeutic development. However, the traditionally siloed, preclinical investigator-driven approaches that have been used to evaluate AKI therapeutics to date rarely account for the limitations of the model systems used and have given rise to false expectations of clinical efficacy in patients with different AKI pathophysiologies. To address this problem, there is a need to develop more flexible and integrated approaches, involving teams of investigators with expertise in a range of different model systems, working closely with clinical investigators, to develop robust preclinical evidence to support more focused interventions in patients with AKI.

Ex-vivo Kidney Machine Perfusion: Therapeutic Potential

Kidney transplantation remains the gold standard treatment for patients suffering from end-stage kidney disease. To meet the constantly growing organ demands grafts donated after circulatory death (DCD) or retrieved from extended criteria donors (ECD) are increasingly utilized. Not surprisingly, usage of those organs is challenging due to their susceptibility to ischemia-reperfusion injury, high immunogenicity, and demanding immune regulation after implantation. Lately, a lot of effort has been put into improvement of kidney preservation strategies. After demonstrating a definite advantage over static cold storage in reduction of delayed graft function rates in randomized-controlled clinical trials, hypothermic machine perfusion has already found its place in clinical practice of kidney transplantation. Nevertheless, an active investigation of perfusion variables, such as temperature (normothermic or subnormothermic), oxygen supply and perfusate composition, is already bringing evidence that ex-vivo machine perfusion has a potential not only to maintain kidney viability, but also serve as a platform for organ conditioning, targeted treatment and even improve its quality. Many different therapies, including pharmacological agents, gene therapy, mesenchymal stromal cells, or nanoparticles (NPs), have been successfully delivered directly to the kidney during ex-vivo machine perfusion in experimental models, making a big step toward achievement of two main goals in transplant surgery: minimization of graft ischemia-reperfusion injury and reduction of immunogenicity (or even reaching tolerance). In this comprehensive review current state of evidence regarding ex-vivo kidney machine perfusion and its capacity in kidney graft treatment is presented. Moreover, challenges in application of these novel techniques in clinical practice are discussed.

Simply Adding Oxygen during Hypothermic Machine Perfusion to Combat the Negative Effects of Ischemia-Reperfusion Injury: Fundamentals and Current Evidence for Kidneys

The use of high-risk renal grafts for transplantation requires optimization of pretransplant preservation and assessment strategies to improve clinical outcomes as well as to decrease organ discard rate. With oxygenation proposed as a resuscitative measure during hypothermic machine preservation, this review provides a critical overview of the fundamentals of active oxygenation during hypothermic machine perfusion, as well as the current preclinical and clinical evidence and suggests different strategies for clinical implementation.

Preservation Solutions for Kidney Transplantation: History, Advances and Mechanisms

Solid organ transplantation was one of the greatest medical advances during the past few decades. Organ preservation solutions have been applied to diminish ischemic/hypoxic injury during cold storage and improve graft survival. In this article, we provide a general review of the history and advances of preservation solutions for kidney transplantation. Key components of commonly used solutions are listed, and effective supplementations for current available preservation solutions are discussed. At cellular and molecular levels, further insights were provided into the pathophysiological mechanisms of effective ingredients against ischemic/hypoxic renal injury during cold storage. We pay special attention to the cellular and molecular events during transplantation, including ATP depletion, acidosis, mitochondrial dysfunction, oxidative stress, inflammation, and other intracellular mechanisms.

Novel Low-Toxic Derivative of Celastrol Maintains Protective Effect against Acute Renal Injury

This study aimed to novelly design and synthesize an amide derivative as a potential substitute of celastrol (CLT). We constituted the compound celastrol-glucosamine (CLG) by conjugating 1-(2-aminoethoxy)-2-glucosamine to celastrol (CLT) and confirmed its chemical structure by ¹H NMR, ¹³C NMR, and LC-MS/MS. Then, the potential efficacy of the CLG was investigated on renal ischemia-reperfusion injury animal models. The results demonstrated that the decorated compound CLG could completely reverse the disease progression as same as CLT. Furthermore, the toxicity of CLG was also fully evaluated in rat blood, liver, kidney, heart, spleen, lung, and reproductive system. Compared to the performance of CLT on normal organs, CLG could remarkably maintain high safety and significantly reduce the side effects. Taken together, the CLG could keep the same efficacy as CLT while processing lower toxicity in vivo.

A Review of Anesthetic Effects on Renal Function: Potential Organ Protection

BACKGROUND

Renal protection is a critical concept for anesthesiologists, nephrologists, and urologists, since anesthesia and renal function are highly interconnected and can potentially interfere with one another. Therefore, a comprehensive understanding of anesthetic drugs and their effects on renal function remains fundamental to the success of renal surgeries, especially transplant procedures. Some experimental studies have shown that some anesthetics provide protection against renal ischemia/reperfusion (IR) injury, but there is limited clinical evidence.

SUMMARY

The effects of anesthetic drugs on renal failure are particularly important in the context of kidney transplantation, since the conditions of preservation following removal profoundly influence the recovery of organ function. Currently, preservation procedures are typically based on the usage of a cold-storage solution. Some anesthetic drugs induce anti-inflammatory, anti-necrotic, and anti-apoptotic effects. A more thorough understanding of anesthetic effects on renal function can present a novel approach for developing organ-protective strategies. The aim of this review is to discuss the effects of different anesthetic drugs on renal function, with particular focus on IR injury. Many studies have demonstrated the organ-protective effects of some anesthetic drugs, specifically propofol, which indicate the potential of some anesthetics to introduce novel organ protective targets. This is not surprising, since lipid emulsions are major components of propofol, which accumulating data show provide organ protective effects against IR injury. Key Messages: Thorough understanding of the interaction between anesthetic drugs and renal function remains fundamental to the delivery of safe perioperative care and to optimizing outcomes after renal surgeries, particularly transplant procedures. Anesthetics can be repurposed for organ protection with more information about their effects, especially during transplant procedures. Here, we review the effects of different anesthetic drugs - specifically those that contain lipids in their structure, with special reference to IR injury.

Hypothermic machine perfusion of kidneys retrieved from standard and high-risk donors

Hypothermic machine perfusion (HMP) of kidneys is a long-established alternative to static cold storage and has been suggested to be a better preservation method. Today, as our deceased donor profile continues to change towards higher-risk kidneys of lower quality, we are confronted with the limits of cold storage. Interest in HMP as a preservation technique is on the rise. Furthermore, HMP also creates a window of opportunity during which to assess the viability and quality of the graft before transplantation. The technology might also provide a platform during which the graft could be actively repaired, making it particularly attractive for higher-risk kidneys. We review the current evidence on HMP in kidney transplantation and provide an outlook for the use of the technology in the years to come.

Celastrol protects kidney against ischemia-reperfusion-induced injury in rats

BACKGROUND

Ischemia-reperfusion (IR) causes various damages in renal tissues, which is exacerbated by hypoxia-induced excessive inflammation and deteriorates the prognosis of patients after kidney surgery. Celastrol is a potent inflammation inhibitor that has little toxicity. In this report, we investigated whether celastrol protects against IR-induced renal injury in rats.

MATERIALS AND METHODS

Renal IR injury was induced by occlusion of the bilateral renal pedicles for 45 min followed by reperfusion for 6 h. Celastrol or vehicle solution was intraperitoneally injected 30 min before renal ischemia, respectively. Renal histology, function, and pro-inflammatory cytokines and mediators were assessed. The effect of celastrol on nuclear translocation of nuclear factor kappa B (NF-κB) was also measured.

RESULTS

Celastrol significantly suppressed elevation of the renal function markers and the lipid peroxidation level, alleviated renal tubular damage, and decreased the levels of tumor necrosis factor-α, interleukin-1β, and monocyte chemotactic protein-1 (MCP-1) messenger RNA in kidney caused by IR. Moreover, celastrol prevented IR-induced expression of pro-inflammatory mediators, which was associated with suppression of nuclear translocation of NF-κB subunit p65.

CONCLUSIONS

Celastrol ameliorated the acute kidney injury caused by IR, which was associated with inhibiting local NF-κB activation and inflammation. Our findings suggest that celastrol could be useful for preventing IR-induced renal injury.